The betrayed is set to be revealed as a betrayer in Sunday's potentially explosive, show-changing episode.

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"The Good Wife," starring Julianna Margulies, is headed in a new direction.

Updated at 1:45 PM PST on Thursday, Oct 24, 2013

"The Good Wife," the story of a political wife's personal and professional comeback from the disgrace wrought by her hooker-happy husband, debuted in 2009, 18 months after Eliot Spitzer’s prostitution scandal erupted and well before Anthony Weiner tweeted himself out of office.

The CBS drama, from the start, came across as more human and realistic than the sex-fueled imbroglios playing out in the increasingly cartoonish realm of politics. The show has proven more durable that many political careers: With its 100th episode nearing, “The Good Wife” remains the strongest and most consistently evolving adult drama on broadcast network TV.

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Now, in a week where the Weiner mess provided inspiration for installments of two shows (“Law & Order: SVU” and “Scandal”) and Mark Sanford's “soul mate” emerged from the shadows, "The Good Wife" is making perhaps its biggest splash yet. Sunday’s episode is shaping up as an explosive game changer, driven by a plot once unthinkable: Julianna Margulies' betrayed wife, Alicia Florrick, becomes a betrayer.

Alicia’s maneuver isn’t about sex – she seemingly got that out of her system via her dangerous affair in Season 3 with her law firm boss and former law school crush, Will Gardner. Her gambit is about power, stealing clients as she semi-secretly starts her own law firm, buoyed by her status as wife of Illinois’ new governor. Which is far sexier than sex, at least in “The Good Wife” universe, a place precariously built on control, corruption, situational ethics and human foibles.

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Margulies, whose facial expressions are worth a thousand words of script, imbues Alicia with the quiet resolve of a woman who will never again allow her fate to be determined – or herself to be defined – by her husband or anyone else. She’s seeking unhindered independence in a legal and political world that too often makes the mistake of underestimating her.

Of course, things never unfold without unexpected repercussions on “The Good Wife.” It’s a show full of twists that presaged the machinations of “House of Cards,” hinging on the constant collisions of Alicia’s personal and professional lives.

“The Good Wife,” which tosses great courtroom drama into the mix, keeps us entertained while rewarding our intelligence and patience. Even when the show seems like it’s coming full circle, it's really just crossing a new line.

Check out preview below of Sunday’s episode, titled “Hitting the Fan,” as "The Good Wife" goes rogue: